red and white cane, got off the E train at Parsons Boulevard and Archer Avenue at around 8 p.m. Wednesday after missing her stop at Jamaica/Van Wyck.

Police sources said the attacker immediately recognized a potential victim and offered to help her.

“Are you lost?” he asked her. “Do you need help?”

She told him she had missed her stop and needed to reverse course.

The thug told the teen the station’s escalators were out of order and promised to guide her to an elevator leading to the southbound platform so she could get back to her station.

The man led her into the elevator, where he placed a sharp object against her neck, pulled her pants below her knees, and raped her against the wall, sources said.

“If you don’t cooperate I’ll cut off more than your hair,” he snarled during the 10-minute assault, sources said.

Immediately afterward, another straphanger helped the victim onto the E train. The victim did not tell this good Samaritan what had happened to her. She kept her awful secret to herself until the next day, when she told her roommate.

The roommate persuaded her to go to cops and stayed with her through the process.

The station where the incident occurred, the last stop on the E line, is a bustling stop in Jamaica where two elevators are in constant use. The MTA said both were operating Wednesday night, as were the escalators.

One police source said the hair-raising subway assault was unprecedented.

“It’s a shocking, heartbreaking case,” said the source. “It’s pure evil what this guy did.”

Queens District Attorney Richard Brown called it one of the most cowardly attacks on record.

“To offer a helping hand to a sightless young woman and then attack her is not merely criminal, it is depraved,” he said.

Even though the victim could not provide a physical description of her assailant, investigators were confident she could recognize his voice.

Sources said investigators had their work cut out for them because the elevator had been scrubbed and bleached between the time of the attack and the call to police.

Anyone with information on the case is urged to call CrimeStoppers at (800) 577-TIPS.

News of Wednesday night’s attack shocked commuters who regularly use the station.

“It’s much too dark in this area, and there’s never enough security,” said Marie Bathelmy, 25, of Brooklyn. “We’re not safe. They need to put in a camera in the elevator and maybe put up some stadium lights.”